My Jaguar has a GMT-400 transmission. Before I purchased the car, the previous owner had replaced it. I did not have any problems for the first two years.

I rebuilt the engine two-years ago, and still did not have any problems.

Last year I put the car in the garage and did not drive it for several months. One day I decided to take it out for a spin, and unexpectedly the distributor cap blew up. Fuel had leaked into the "V" under the distributor Cap.

Since I was working on the car, I decided to go ahead and do some work, replacing the U-joints. I noticed a small leak around the transmission gasket. So I decided to replace the fluid and filter, cleaning the pan as well.

Everything seemed OK.

Again the car sat for several months until January when I was sent to Washington State. I took the car with me on a U-Haul Transporter. While in Washington State I never had a problem. When I returned I put the car in the garage where it has sat. Several weeks ago, I opened the garage door and found a large pool of transmission fluid on the floor. I had hurt my back the week before and could not investigate it. I placed kitty litter on it and clean up as much as I could.

Since then I have had to replace kitty litter on the floor as the fluid keeps coming out.

My questions are,
1) What might be the problem in the first place? Is it a front seal?
2) I am confident in my abilities to take on the task of rebuilding a transmission, are there any kits available for the GMT-400?
3) Is the 700R4 a better transmission and is it easier to rebuild with an above average supply of home shop tools?

The reason I am thinking about undertaking this project is that when I had it priced, it was going to cost me a minimum of $1,500. A big amount to try and sneak past the boss (wife). Otherwise I have plenty of time on my hands.

It's possible that the shop that rebuilt the trans felt the shifter lever seal (o-rings) was good enough not to replace, or forgot too. The trans won't have to come out, but I'm pretty sure the valve body has to be dropped. Be VERY careful when removing the valve body! DO NOT tilt it or turn over, as there are small valve balls and some springs that can fall out, and you can't usually tell where they go back without a manual.

Other than the pan gasket, the only other two likely sources are the front and rear seals. If the fluid looks like it's coming from the bell housing, it's the front seal. The trans has to come out for that. Any time the trans is out, regardless of how recent it was replaced, replace the front seal! Good preventive maintenance. If I had to pull a trans a month after replacing it, I'd still replace the $5-$10 seal. Better than having to pull the trans again!! If it's the rear seal, of course, it should be obvious.

How long does the car sit? If it leaks some, don't top it back off until ready to drive. On some trannies the fluid in the converter can drain back into the trans when it sits for long periods (say over a week) and cause an overfull condition in the trans body. Then it may leak in places it otherwise wouldn't

It's possible that the shop that rebuilt the trans felt the shifter lever seal (o-rings) was good enough not to replace, or forgot too. The trans won't have to come out, but I'm pretty sure the valve body has to be dropped.

NOT SO ...

KD makes a tool ( about 10 dollars or so ) ... to remove and install the shifter seal without even removing the pan. Just remove the shifter arm ...

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